The subject matter disclosed herein generally relates to fasteners and, more particularly, to sliding fastener systems.
Joining components subject to differential thermal growth presents challenges, particularly in demanding aerospace applications. Differential thermal growth between two components may occur as a result of thermal gradients between two joined parts (e.g., one part is hotter than the other) or as a result of different rates of thermal expansion between the materials in the two components. One challenge is the accommodation of the different thermal growths at the interface between the components without creating large loads and high stresses. For example, in an aerospace application, aluminum strakes may be attached to composite fan cowls. When the aircraft is in cruise at high altitudes and subject to low ambient temperatures, the aluminum strake contracts at a much greater rate than the composite fan cowl. If the strake and the fan cowl are tightly clamped together and the joint completely restrained, then the differential growth will resolve into different types of loads and stresses in the strake, the fan cowl, and the fasteners that join them. The problem can be particularly acute in the fasteners between two joined components with differential thermal expansion, as the fasteners may suffer from fatigue if there are many cycles of expansion and contraction. In general, a preferred attachment philosophy in this type of situation is to allow the components to move relative to each other at the joint, at least partially (i.e., allow the thermal expansion be unrestrained or at least partially unrestrained), in order to avoid generating the large loads and high stresses. The attachment methodology described herein allows such movement, while still maintaining an overall sound fastener joint.